diff options
| -rw-r--r-- | Documentation/device-mapper/statistics.txt | 28 | ||||
| -rw-r--r-- | drivers/md/dm-stats.c | 138 | ||||
| -rw-r--r-- | drivers/md/dm-stats.h | 4 |
3 files changed, 127 insertions, 43 deletions
diff --git a/Documentation/device-mapper/statistics.txt b/Documentation/device-mapper/statistics.txt index 2a1673a..ff6baea 100644 --- a/Documentation/device-mapper/statistics.txt +++ b/Documentation/device-mapper/statistics.txt @@ -13,9 +13,13 @@ the range specified. The I/O statistics counters for each step-sized area of a region are in the same format as /sys/block/*/stat or /proc/diskstats (see: Documentation/iostats.txt). But two extra counters (12 and 13) are -provided: total time spent reading and writing in milliseconds. All -these counters may be accessed by sending the @stats_print message to -the appropriate DM device via dmsetup. +provided: total time spent reading and writing. All these counters may +be accessed by sending the @stats_print message to the appropriate DM +device via dmsetup. + +The reported times are in milliseconds and the granularity depends on +the kernel ticks. When the option precise_timestamps is used, the +reported times are in nanoseconds. Each region has a corresponding unique identifier, which we call a region_id, that is assigned when the region is created. The region_id @@ -33,7 +37,9 @@ memory is used by reading Messages ======== - @stats_create <range> <step> [<program_id> [<aux_data>]] + @stats_create <range> <step> + [<number_of_optional_arguments> <optional_arguments>...] + [<program_id> [<aux_data>]] Create a new region and return the region_id. @@ -48,6 +54,17 @@ Messages "/<number_of_areas>" - the range is subdivided into the specified number of areas. + <number_of_optional_arguments> + The number of optional arguments + + <optional_arguments> + The following optional arguments are supported + precise_timestamps - use precise timer with nanosecond resolution + instead of the "jiffies" variable. When this argument is + used, the resulting times are in nanoseconds instead of + milliseconds. Precise timestamps are a little bit slower + to obtain than jiffies-based timestamps. + <program_id> An optional parameter. A name that uniquely identifies the userspace owner of the range. This groups ranges together @@ -55,6 +72,9 @@ Messages created and ignore those created by others. The kernel returns this string back in the output of @stats_list message, but it doesn't use it for anything else. + If we omit the number of optional arguments, program id must not + be a number, otherwise it would be interpreted as the number of + optional arguments. <aux_data> An optional parameter. A word that provides auxiliary data diff --git a/drivers/md/dm-stats.c b/drivers/md/dm-stats.c index d1fd31a..4bfd84a 100644 --- a/drivers/md/dm-stats.c +++ b/drivers/md/dm-stats.c @@ -33,13 +33,14 @@ struct dm_stat_percpu { struct dm_stat_shared { atomic_t in_flight[2]; - unsigned long stamp; + unsigned long long stamp; struct dm_stat_percpu tmp; }; struct dm_stat { struct list_head list_entry; int id; + unsigned stat_flags; size_t n_entries; sector_t start; sector_t end; @@ -53,6 +54,8 @@ struct dm_stat { struct dm_stat_shared stat_shared[0]; }; +#define STAT_PRECISE_TIMESTAMPS 1 + struct dm_stats_last_position { sector_t last_sector; unsigned last_rw; @@ -224,7 +227,8 @@ void dm_stats_cleanup(struct dm_stats *stats) } static int dm_stats_create(struct dm_stats *stats, sector_t start, sector_t end, - sector_t step, const char *program_id, const char *aux_data, + sector_t step, unsigned stat_flags, + const char *program_id, const char *aux_data, void (*suspend_callback)(struct mapped_device *), void (*resume_callback)(struct mapped_device *), struct mapped_device *md) @@ -265,6 +269,7 @@ static int dm_stats_create(struct dm_stats *stats, sector_t start, sector_t end, if (!s) return -ENOMEM; + s->stat_flags = stat_flags; s->n_entries = n_entries; s->start = start; s->end = end; @@ -414,18 +419,24 @@ static int dm_stats_list(struct dm_stats *stats, const char *program, return 1; } -static void dm_stat_round(struct dm_stat_shared *shared, struct dm_stat_percpu *p) +static void dm_stat_round(struct dm_stat *s, struct dm_stat_shared *shared, + struct dm_stat_percpu *p) { /* * This is racy, but so is part_round_stats_single. */ - unsigned long now = jiffies; - unsigned in_flight_read; - unsigned in_flight_write; - unsigned long difference = now - shared->stamp; + unsigned long long now, difference; + unsigned in_flight_read, in_flight_write; + + if (likely(!(s->stat_flags & STAT_PRECISE_TIMESTAMPS))) + now = jiffies; + else + now = ktime_to_ns(ktime_get()); + difference = now - shared->stamp; if (!difference) return; + in_flight_read = (unsigned)atomic_read(&shared->in_flight[READ]); in_flight_write = (unsigned)atomic_read(&shared->in_flight[WRITE]); if (in_flight_read) @@ -440,8 +451,9 @@ static void dm_stat_round(struct dm_stat_shared *shared, struct dm_stat_percpu * } static void dm_stat_for_entry(struct dm_stat *s, size_t entry, - unsigned long bi_rw, sector_t len, bool merged, - bool end, unsigned long duration) + unsigned long bi_rw, sector_t len, + struct dm_stats_aux *stats_aux, bool end, + unsigned long duration_jiffies) { unsigned long idx = bi_rw & REQ_WRITE; struct dm_stat_shared *shared = &s->stat_shared[entry]; @@ -471,15 +483,18 @@ static void dm_stat_for_entry(struct dm_stat *s, size_t entry, p = &s->stat_percpu[smp_processor_id()][entry]; if (!end) { - dm_stat_round(shared, p); + dm_stat_round(s, shared, p); atomic_inc(&shared->in_flight[idx]); } else { - dm_stat_round(shared, p); + dm_stat_round(s, shared, p); atomic_dec(&shared->in_flight[idx]); p->sectors[idx] += len; p->ios[idx] += 1; - p->merges[idx] += merged; - p->ticks[idx] += duration; + p->merges[idx] += stats_aux->merged; + if (!(s->stat_flags & STAT_PRECISE_TIMESTAMPS)) + p->ticks[idx] += duration_jiffies; + else + p->ticks[idx] += stats_aux->duration_ns; } #if BITS_PER_LONG == 32 @@ -491,7 +506,7 @@ static void dm_stat_for_entry(struct dm_stat *s, size_t entry, static void __dm_stat_bio(struct dm_stat *s, unsigned long bi_rw, sector_t bi_sector, sector_t end_sector, - bool end, unsigned long duration, + bool end, unsigned long duration_jiffies, struct dm_stats_aux *stats_aux) { sector_t rel_sector, offset, todo, fragment_len; @@ -520,7 +535,7 @@ static void __dm_stat_bio(struct dm_stat *s, unsigned long bi_rw, if (fragment_len > s->step - offset) fragment_len = s->step - offset; dm_stat_for_entry(s, entry, bi_rw, fragment_len, - stats_aux->merged, end, duration); + stats_aux, end, duration_jiffies); todo -= fragment_len; entry++; offset = 0; @@ -529,11 +544,13 @@ static void __dm_stat_bio(struct dm_stat *s, unsigned long bi_rw, void dm_stats_account_io(struct dm_stats *stats, unsigned long bi_rw, sector_t bi_sector, unsigned bi_sectors, bool end, - unsigned long duration, struct dm_stats_aux *stats_aux) + unsigned long duration_jiffies, + struct dm_stats_aux *stats_aux) { struct dm_stat *s; sector_t end_sector; struct dm_stats_last_position *last; + bool got_precise_time; if (unlikely(!bi_sectors)) return; @@ -557,8 +574,17 @@ void dm_stats_account_io(struct dm_stats *stats, unsigned long bi_rw, rcu_read_lock(); - list_for_each_entry_rcu(s, &stats->list, list_entry) - __dm_stat_bio(s, bi_rw, bi_sector, end_sector, end, duration, stats_aux); + got_precise_time = false; + list_for_each_entry_rcu(s, &stats->list, list_entry) { + if (s->stat_flags & STAT_PRECISE_TIMESTAMPS && !got_precise_time) { + if (!end) + stats_aux->duration_ns = ktime_to_ns(ktime_get()); + else + stats_aux->duration_ns = ktime_to_ns(ktime_get()) - stats_aux->duration_ns; + got_precise_time = true; + } + __dm_stat_bio(s, bi_rw, bi_sector, end_sector, end, duration_jiffies, stats_aux); + } rcu_read_unlock(); } @@ -571,7 +597,7 @@ static void __dm_stat_init_temporary_percpu_totals(struct dm_stat_shared *shared local_irq_disable(); p = &s->stat_percpu[smp_processor_id()][x]; - dm_stat_round(shared, p); + dm_stat_round(s, shared, p); local_irq_enable(); memset(&shared->tmp, 0, sizeof(shared->tmp)); @@ -643,11 +669,15 @@ static int dm_stats_clear(struct dm_stats *stats, int id) /* * This is like jiffies_to_msec, but works for 64-bit values. */ -static unsigned long long dm_jiffies_to_msec64(unsigned long long j) +static unsigned long long dm_jiffies_to_msec64(struct dm_stat *s, unsigned long long j) { - unsigned long long result = 0; + unsigned long long result; unsigned mult; + if (s->stat_flags & STAT_PRECISE_TIMESTAMPS) + return j; + + result = 0; if (j) result = jiffies_to_msecs(j & 0x3fffff); if (j >= 1 << 22) { @@ -709,16 +739,16 @@ static int dm_stats_print(struct dm_stats *stats, int id, shared->tmp.ios[READ], shared->tmp.merges[READ], shared->tmp.sectors[READ], - dm_jiffies_to_msec64(shared->tmp.ticks[READ]), + dm_jiffies_to_msec64(s, shared->tmp.ticks[READ]), shared->tmp.ios[WRITE], shared->tmp.merges[WRITE], shared->tmp.sectors[WRITE], - dm_jiffies_to_msec64(shared->tmp.ticks[WRITE]), + dm_jiffies_to_msec64(s, shared->tmp.ticks[WRITE]), dm_stat_in_flight(shared), - dm_jiffies_to_msec64(shared->tmp.io_ticks_total), - dm_jiffies_to_msec64(shared->tmp.time_in_queue), - dm_jiffies_to_msec64(shared->tmp.io_ticks[READ]), - dm_jiffies_to_msec64(shared->tmp.io_ticks[WRITE])); + dm_jiffies_to_msec64(s, shared->tmp.io_ticks_total), + dm_jiffies_to_msec64(s, shared->tmp.time_in_queue), + dm_jiffies_to_msec64(s, shared->tmp.io_ticks[READ]), + dm_jiffies_to_msec64(s, shared->tmp.io_ticks[WRITE])); if (unlikely(sz + 1 >= maxlen)) goto buffer_overflow; @@ -769,21 +799,31 @@ static int message_stats_create(struct mapped_device *md, unsigned long long start, end, len, step; unsigned divisor; const char *program_id, *aux_data; + unsigned stat_flags = 0; + + struct dm_arg_set as, as_backup; + const char *a; + unsigned feature_args; /* * Input format: - * <range> <step> [<program_id> [<aux_data>]] + * <range> <step> [<extra_parameters> <parameters>] [<program_id> [<aux_data>]] */ - if (argc < 3 || argc > 5) + if (argc < 3) return -EINVAL; - if (!strcmp(argv[1], "-")) { + as.argc = argc; + as.argv = argv; + dm_consume_args(&as, 1); + + a = dm_shift_arg(&as); + if (!strcmp(a, "-")) { start = 0; len = dm_get_size(md); if (!len) len = 1; - } else if (sscanf(argv[1], "%llu+%llu%c", &start, &len, &dummy) != 2 || + } else if (sscanf(a, "%llu+%llu%c", &start, &len, &dummy) != 2 || start != (sector_t)start || len != (sector_t)len) return -EINVAL; @@ -791,7 +831,8 @@ static int message_stats_create(struct mapped_device *md, if (start >= end) return -EINVAL; - if (sscanf(argv[2], "/%u%c", &divisor, &dummy) == 1) { + a = dm_shift_arg(&as); + if (sscanf(a, "/%u%c", &divisor, &dummy) == 1) { if (!divisor) return -EINVAL; step = end - start; @@ -799,18 +840,39 @@ static int message_stats_create(struct mapped_device *md, step++; if (!step) step = 1; - } else if (sscanf(argv[2], "%llu%c", &step, &dummy) != 1 || + } else if (sscanf(a, "%llu%c", &step, &dummy) != 1 || step != (sector_t)step || !step) return -EINVAL; + as_backup = as; + a = dm_shift_arg(&as); + if (a && sscanf(a, "%u%c", &feature_args, &dummy) == 1) { + while (feature_args--) { + a = dm_shift_arg(&as); + if (!a) + return -EINVAL; + if (!strcasecmp(a, "precise_timestamps")) + stat_flags |= STAT_PRECISE_TIMESTAMPS; + else + return -EINVAL; + } + } else { + as = as_backup; + } + program_id = "-"; aux_data = "-"; - if (argc > 3) - program_id = argv[3]; + a = dm_shift_arg(&as); + if (a) + program_id = a; + + a = dm_shift_arg(&as); + if (a) + aux_data = a; - if (argc > 4) - aux_data = argv[4]; + if (as.argc) + return -EINVAL; /* * If a buffer overflow happens after we created the region, @@ -822,7 +884,7 @@ static int message_stats_create(struct mapped_device *md, if (dm_message_test_buffer_overflow(result, maxlen)) return 1; - id = dm_stats_create(dm_get_stats(md), start, end, step, program_id, aux_data, + id = dm_stats_create(dm_get_stats(md), start, end, step, stat_flags, program_id, aux_data, dm_internal_suspend_fast, dm_internal_resume_fast, md); if (id < 0) return id; diff --git a/drivers/md/dm-stats.h b/drivers/md/dm-stats.h index e7c4984..f1c0956 100644 --- a/drivers/md/dm-stats.h +++ b/drivers/md/dm-stats.h @@ -18,6 +18,7 @@ struct dm_stats { struct dm_stats_aux { bool merged; + unsigned long long duration_ns; }; void dm_stats_init(struct dm_stats *st); @@ -30,7 +31,8 @@ int dm_stats_message(struct mapped_device *md, unsigned argc, char **argv, void dm_stats_account_io(struct dm_stats *stats, unsigned long bi_rw, sector_t bi_sector, unsigned bi_sectors, bool end, - unsigned long duration, struct dm_stats_aux *aux); + unsigned long duration_jiffies, + struct dm_stats_aux *aux); static inline bool dm_stats_used(struct dm_stats *st) { |